Mercia's dominance of southern England rapidly unravels…

Pegu, on the Pegu River in southern Burma, is founded in about 825 as the capital of the Mon state, which is organized according to Indian political principles and ruled by kings held to be divine.

Kukai, the founder of the Shingon or "True Word" school of Buddhism, establishes Zenpuku-ji, a Shingon Buddhist temple in 824, located in the Azabu district of present Tokyo, Japan.

It is today one of the oldest Tokyo temples, after the Sensō-ji in Asakusa, founded in 628.

The expanding Bai kingdom of Nanzhao captures the city of Chengdu in Sichuan province, China.

It is a great prize, as it enables Nanzhao to lay claim to the whole of Sichuan province, with its rich paddy fields.

This is too much for the Tang Dynasty, who lose no time in counterattacking.

Omurtag now turns his attention northwards.

Memorial inscriptions set up for Omurtag's dead officials indicate that his jurisdiction and troops had reached the river Dnieper in the east (campaigning against the Khazars or Magyars) and the Tisza in the west.

The Slavic tribes of the Timočani, Abodrites, and Braničevci had rebelled in 818 against the increasingly onerous Bulgarian suzerainty in the west and sought the support of the Frankish Emperor Louis the Pious.

Omurtag approaches the Frankish court in 824 and 825 in an attempt to seek a diplomatic resolution of the problem.

Alfonso II and the Consolidation of the Kingdom of Asturias

The Kingdom of Asturias gains firm recognition as a legitimate Christian realm only after both Charlemagne and the Pope acknowledge Alfonso II as its rightful king.

After securing sovereignty over Galicia and the Basques, Alfonso II achieves decisive victories over the Moors at Narón and Anceo in 825. These triumphs allow him to repopulate key territories in Galicia and the regions that will later form the Kingdoms of León and Castile, laying the foundation for the Christian Reconquista of Iberia.

Louis continues and expands his father's liberal policies toward the Jews, changing Market day from the Sabbath to Sunday in 825 and appointing one Ebeard, a Jew, as magister judeacrum to protect Jewish rights.

His need for Jewish money making him beholden to Jewish merchants, Louis issues to the Jews a Charter of Protection, encourages Jewish trade (including slave trade) and relaxes political restrictions, allowing some juridical autonomy.

Teaching begins at Oxford in 825 according to documents held by University College, Oxford and All Souls College, Oxford. (The University of Oxford will not be founded until 1096; its collegiate structure will develop even later.)

Mercia holds a dominant position among the Anglo-Saxon kingdoms of the Heptarchy.

Ater its king, Ceolwulf, had been overthrown in 823, Beornwulf, the son of a noble, had become king. (The Mercians had conquered Powys at about this time, but it is unclear which of the two kings was ruling when it occurred.

Scholars have argued that the known record suggests that Beornwulf was more vigorous and likely to wage such a campaign than Ceolwulf, and that the conquest of Powys may have therefore been accomplished by Beornwulf at the beginning of his rule.)

Soon after assuming the kingship, Beornwulf had rebuilt the Abbey of St. Peter, the future Gloucester Cathedral.

He presides in 824 and 825 over two synods at Clofesho (an unknown location believed to be near London) with archbishop Wulfred of Canterbury.

Beornwulf attacks the West Saxons but King Egbert of Wessex in September 825 defeats and slays him at Ellandun, identified with Wroughton in Wrightshire, to become the eighth Bretwalda (overlord) and the first Anglo-Saxon king to be styled "ruler over all England."

Ecgbert's son Æðelwulf invades Kent subsequent to the Battle of Ellandun, and drives out its pro-Mercian king, Baldred.